The quest for exoplanets of astrobiological interest is driven by the possibility of the presence of liquid water, but also of an efficient organic chemistry. Titan, the largest moon of Saturn, with a global structure similar to the Earth (a solid surface with liquid areas, and a dense atmosphere mainly composed of nitrogen) is one of the most interesting models for defining the astrobiological interest of exoplanets through possibly associated exomoons. An intense atmospheric chemistry is indeed being revealed by the ongoing Cassini-Huygens space mission. Photo-dissociation and ionization of its major constituents, N2 and CH4, initiate a complex network of reactions, leading to solid organic aerosols responsible for an organic smog surrounding permanently the satellite. In this work we will discuss how far this complex organic chemistry involving nitrogen is understood and the impact for the production of atmospheric aerosols.